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Advantages of Critacal Chain

7 replies [Last post]
Sun, 2006-04-23 04:42
Jaco Stadler
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I am Busy with the advantages of Critical Chain.

Any Ideas ???
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Wed, 2006-04-26 02:52
#1
Vladimir Liberzon
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We used Just in time for supplies management (there was not room for storage at the construction site).
Postponing non-critical activities don’t forget to add necessary contingency reserves (Critical Chain theory calls them feeding buffers) to their late finish.
And of course project schedule shall be calculated taking into account resource and supplies limitations.
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Wed, 2006-04-26 01:20
#2
Jaco Stadler
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Morning Alistair

I am not here to argue the point all I am looking for is some planners who are familiar with this and who understand Just in time scheduling and their opinion of Just in Time.

Cheers


Typical Project utilised is Mega Project.
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Tue, 2006-04-25 04:03
#3
Alistair Blakey
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I agree with Vladimir - leaving things to the last minute just leads to real delays if that activity is further delayed by an unforseen event.

Looking at your points in turn

1. Surely by your approach all activities will be hyper-critical, with any delay affecting the completion date. Not even considering an activity untill it becomes critical will lead to an increased drain on resources and higher resource peaks (see 6 below!)

2. Using your Critical Chain, planned dates are not realistic, they are merely at the last possible moment - any problem will impact directly on the activity’s end date and hence on the project end date and thus have a negative impact on the team as they have to work overtime to make up the lost time!

3. Depends on the form of contract used - a monthly payment though will mean that the interest incurred on negative cashflow would be the same whenever in the timeline it is incurred.

4. Again depends on the agreements made with suppliers

5. Proper scheduling and planning means getting goods in just before they are installed on site, not just before their installation on site is critical

6. Possibly the most contemptible argument of the lot! The ability to complete activities before they become critical can be extremely effective in reducing the resource peak and generating float (i.e. reducing risk) in the programme.

Just my two cents... what type of projects are likely to promote the use of "critical chain" Jaco?

Regards,
Alistair
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Tue, 2006-04-25 00:59
#4
Jaco Stadler
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Morning

I Disagree.

How can the risk increases. It would actualy decreases.

What it does it ensure that your resources are focused on the longest path activity’s and not on non Critical activity’s. If You work on Early or Mean you will stil be spending resources on non critical activity’s

The Advantages that I Came up with are

1) Resource More Concentrated on True Critical Activity rather than Non Critical.
2) Planned Dates More Realistic and the Team feel they can achieve the Planned Dates. (Positive Project team)
3) Cash flow Delayed (Less Interest Incurred)
4) Less Money Spend Warrantee Periods
5) Less money spend on Storage
6) No Short Period Resources required (less of a peak on resource Histograms

So Does any body have anything to add.


Cheers
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Mon, 2006-04-24 13:06
#5
Vladimir Liberzon
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What you described is not Critical Chain approach. It is just in time approach as you called it yourself. And to do it the way you described is very risky.
Just in time helps to minimize costs but increases risks.
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Mon, 2006-04-24 06:36
#6
Jaco Stadler
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To Me the Critical Chain is all Activity’s are Critical
I Have heard a lot of Term for this - Just in Time etc.

It is in short working backwords from the finish. (Only using a Backward pass dates rather than a Forward Pass.

What is the advantages on this method rather than utilising normal Forward pass. (Early Start)
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Sun, 2006-04-23 08:48
#7
Vladimir Liberzon
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What do you mean?
I wrote earlier that we used approaches similar to those suggested by Goldratt for a long time (actually since 1992). We call Resource Critical Path what you call Critical Chain. Critical Chain buffers actually are contingency reserves calculated by risk analysis and simulation. Maybe I can help if you will ask specific questions.
Regards,
Vladimir
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